If the recent departures of Italian Prime Minister Silvio Berlusconi and Greek Prime Minister George Papandreou were not enough to demonstrate the power of economic crisis to bring down entrenched political leadership, witness Spain's Nov. 20 elections.

Outgoing Prime Minister Jos Luis Rodrguez Zapatero pulled Spain's troops out of Iraq within weeks of taking office in 2004, legalized gay marriage, cracked down on domestic violence, eased access to abortion and divorce and helped bring an end to the 40-year scourge of terrorism by the Basque separatist group...